Note: For some diesel models of the last years of production, equipped with a Z19DT engine (H), AT brand AF40 can be installed - it is not covered in this manual.
1. On the models described in this manual, an automatic 5-speed AT with Active Select - AF23 / AF33 is installed, which allows you to control gear shifting, both in automatic and manual mode, or a 6-speed AT - VT20-E with a system CVTronic with three control modes (see chapter «Controls and methods of operation»). Automatic transmissions AF23 and AF33 are practically the same gearbox, but adapted to different engines and final drive ratios, and controlled by different programs. Identification number and code are printed on the nameplate attached to the transmission housing (see resist. illustration).
1.1 AT identification number (F23/F33)
2. AT consists of a torque converter (rotation converter), planetary assembly and hydraulically controlled clutches (clutches) and brake bands. The operation of the transmission is controlled by an electronic module through electrically controlled valves. AT can operate in one of three modes: normal, winter, and on models of recent years of production - sports. The order of switching on and the purpose of the modes are described in more detail in Chapter «Controls and methods of operation», Section 25.
3. Torque converter (rotation converter) transfers torque from the engine to the gearbox. Due to the fact that the transmission of rotation is carried out hydraulically (through the transmission fluid - ATF), starting off the car and shifting gears are very smooth. In addition, the torque converter provides dynamic torque adjustments during acceleration.
4. The AT planetary gear provides five forward gears and one reverse gear selection. The gear ratio of a planetary gearbox is determined by which of its elements are locked and which rotate freely. The blocking and release of the elements of the planetary assemblies in the AT is carried out using clutches and brake bands, activated by commands from the control module. The hydraulic pump placed inside the transmission housing creates the pressure of the working fluid necessary to activate the clutches and brake bands.
5. The driver controls the AT using the selector lever mounted on the floor of the vehicle. Control methods are described in detail in Chapter «Controls and methods of operation».
6. Due to the complexity of the AT's design, the lack of commercially available interchangeable internal components, and the need for special equipment, the authors of this manual do not recommend that vehicle owners perform a major transmission overhaul on their own. In this Chapter, only the procedures for diagnosing general transmission failures, its current maintenance, individual adjustments, removal and installation are considered.
7. In the event of a serious breakdown, it is wiser and easier to replace the transmission than to spend time and money on restoring a failed assembly. However, doing the removal and installation yourself can greatly reduce costs (first make sure that the transmission really needs refurbishment).
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